PAPPA and atherosclerosis: In 2007, Harrington et al. [60] crossed the PAPP-A knockout mice (PAPP-A KO) with apolipoprotein E knockout mice (ApoE KO) (established model for atherosclerosis) and found that KO/KO mice showed a 70–80% reduction in atherosclerotic lesion area compared to ApoE KO mice on a high fat diet.